1. Field of the Invention
The present invention relates to an apparatus for detecting the position of any faulty light emitting element upon occurrence of failure in one or more of multiple display elements arrayed on the screen of a large-sized display system.
2. Description of the Prior Art
In the recent sports stadiums or the like such as baseball stadiums, soccer stadiums and so forth where multiple spectators gather, there is practically used a large screen display system--e.g. known by the trade name of Aurora Vision or Diamond Vision--which is equipped with a multiplicity of light emitting sources arrayed in columns and rows to constitute a large-sized screen and displays still images, motion images, characters and so forth on such screen for giving specific information to the spectators.
The above large screen display system principally comprises a display means including a large-sized screen, a power supply panel and a display controller; and an operating means including a computer, a character editing terminal, a screen control terminal and a special effect switcher. The large-sized screen is composed of a multiplicity of light emitting elements such as incandescent lamps or light source tubes of recently developed high-luminance CRTs which are arrayed in columns and rows vertically and horizontally to constitute a combination of many units in accordance with the screen size, wherein each unit is composed of a predetermined number of such elements as, for example, 4.times.8=32.
When there occur faults of multiple light emitting elements in the display means constituting the large screen, the information such as images or characters displayed on the screen fail to be transmitted properly to the spectators, so that fast replacement or repair of the faulty elements is necessary. And to perform such repair, it is requisite to first detect which of the multiple light emitting elements are faulty.
In the prior art, there is known one exemplary apparatus of FIGS. 1 and 2 for positional detection of faulty light emitting elements, wherein a large screen 2 of a large-sized display system 1 is composed of a multiplicity of display units 3 . . . and is connected to an unshown display controller. Each of the display units 3 consists of, for example, an array of 32 light emitting elements 4 (eight in a row and four in a column) such as incandescent lamps or high-luminance CRTs (cathode-ray tubes), and the elements 4 are assorted in three primary colors as red (R), blue (B) and green (G). In an arbitrary display unit 3n out of the entire units 3 in FIG. 1, the light emitting elements 4 are arrayed as illustrated.
For detection of any fault such as breaking or luminance reduction in the individual light emitting elements 4 . . . of the display unit 3n, a faulty-element position detecting apparatus 10 is employed. The detecting apparatus 10 principally comprises a power supply 11 fed with external detecting power via a power cable 12, and a detector 21 disposed above the power supply 11 and serving to detect the position of each faulty light emitting element. An operating panel 13 is disposed on the front of the power supply 11 and is equipped with a voltmeter 14, an ammeter 15, a selector switch 16 for selecting a desired lighting display mode such as lighting of all elements of a unit or lighting of half elements of a unit or lighting of each element of a unit and a lighting switch 17 for simultaneously turning on the entire light emitting elements in the display unit 3. Three cables extending from the detector 21 have, at the fore ends thereof, plugs connectable to connectors (not shown) of the display unit 3. The cables consist of an output data cable 22, a set/reset signal cable 23 and a DC power/AC power cable 24 for respectively supplying an output data signal, a set/reset signal and a DC power/AC power from the detector 21 to the display unit 3. Light acceptant parts 25 . . . for insertion of luminous parts pointed ends of the light emitting elements 4 . . . on the back of the display unit 3 are arrayed on the front of the detector 21 correspondingly to the light emitting elements 4 . . . , and unit testing positioners 18 and 19 are disposed in front of the light acceptant parts 25 above the power supply 11. A luminance adjusting dial assembly 26 is disposed above the light acceptant parts 25 . . . of the detector 21 so that, for example, the luminance of red light emitting elements R can be adjusted by a dial 26a, the luminance of blue light emitting elements B by a dial 26b, and the luminance of green light emitting elements G by a dial 26c, respectively. On the panel where the luminance adjusting dial assembly 26 is located, pairs of light emitting diodes (LEDS) 27 and 28 are provided for the individual light emitting elements of the display unit 3. For example, each pair of such LEDs consists of a diode 27 turned on at the luminance of a predetermined low level and a diode 28 turned on at the luminance of a predetermined high level.
In the faulty-element position detecting apparatus 10 having the above-described structure, the following operation is performed.
First, as shown in FIG. 1, an arbitrary display unit 3n in the large screen 2 of the large display system 1 is removed from the screen 2. Then the display unit 3n is slid as shown in FIG. 2 along the unit testing positioners 18 and 19 located above the power supply 11 of the position detecting apparatus 10, and luminous parts as pointed ends of the light emitting elements 4 are inserted into the light acceptant parts 25 . . . of the detector 21 in the position detecting apparatus 10. And simultaneously the lighting test cables 22-24 are connected to unshown connectors of the display unit 3n.
In a test for detecting any fault such as breaking of the light emitting elements 4 . . . , the lighting switch 17 is turned on to supply power to the display unit 3n through the cables 22-24, and the operator visually checks whether the entire light emitting elements 4 . . . (e.g. 32 elements in the example illustrated) arrayed in the display unit 3n are turned on. In case one of the light emitting elements 4 . . . fails to be turned on, the faulty element 4n is replaced.
Subsequently, when detecting whether luminance reduction is present or not in any of the light emitting elements 4 . . . , scale "ALL" is selected by the selector switch 16 after placing the display unit 3n at a prescribed position. Since the entire light emitting elements 4 . . . of the display unit 3n are turned on, it is possible by adjustment of the individual dials 26 to check whether a predetermined luminance as a whole is retained or not from turn-on of the LEDs 27 and 28.
Relative to the conventional faulty-element position detecting apparatus of the aforementioned structure that performs the above operation, an exemplary circuit configuration is disclosed in Patent Publication No. 55 (1980)-749 issued from the Japanese Patent Office. However, "Electric Display Board Monitoring Apparatus" according to the above invention is not equipped with a circuit to conduct a luminance reduction test. In the aforementioned procedure, the operator detects a faulty light emitting element 4n visually with his naked eyes by sequentially turning on the light emitting elements 4. Meanwhile the apparatus disclosed in the above patent publication is equipped with "a circuit for scanning and detecting the presence or absence of a breaking signal", so that it is capable of automatically counting the number of faulty light emitting elements by means of a counter and displaying the positions thereof in a continuous lighting test mode selected by setting at scale "SEQ".
However, there still exist the following problems in such conventional detecting apparatus.
Firstly, in conducting the above test by sequentially removing the entire display units 3 . . . incorporated in the large screen 2 of the large display system 1 and setting each display unit in the detecting apparatus 10, an excessive burden is imposed on the operator and, with dimensional increase of the large display system 1, positional detection of faulty light emitting elements is operationally complicated to consequently bring about a failure in achieving complete and precise maintenance of the large display system 1.
Secondly, in case no scanning detection circuit is provided, the detection is dependent mostly on the visual inspection by the operator, and therefore exact positional detection of a faulty light emitting element is not attainable. And even with the provision of a scanning detection circuit, visual inspection is still requisite in the process of finding, out of the large screen 2, the display unit 3n where the faulty light emitting element is existent, hence rendering accurate detection of the faulty portion impossible.
Thirdly, in the conventional position detecting apparatus where the scale "ALL", "HALF" or "SEQ" is selected by the test-mode setting switch 16 to conduct a test in each selected mode as well as a lighting test and a luminance reduction test, it is impossible to individually detect a breaking fault or luminance reduction with respect to any specific light emitting element 4, and regardless of such inevitable removal of each display unit 3 from the large screen 2 for testing, the detecting operation is rather rough and exact control is not achievable for the system, hence lacking in reliability for detection of any faulty light emitting element.
And fourthly, for enabling continuous use of the large display system 1, it is necessary to install a large-sized position detecting apparatus 10 which is dimensionally a multiple of the display unit 3 and, as the number or size of display units 3 . . . becomes greater with further dimensional extension of the display system 1, there arise some problems to be taken into consideration, such as increased economical burden on purchasers, need of a sufficient space for installation of the position detecting apparatus and so forth.